NASA's Dawn spacecraft is currently in the final stages of its historic mission to place a satellite in orbit around the dwarf planet Ceres. The primary mission will take 16 months and will see the robotic explorer capture detailed images and measurements of Ceres, greatly improving our knowledge of the solar system.
Launched in 2007 from Cape Canaveral Air Force Base atop a Delta II rocket, Dawn carries a state-of-the-art suite of scientific equipment. This is designed to allow the spacecraft to unlock some of the mysteries surrounding the formation of our early solar system via a detailed observation of the rocky body Vesta, and the dwarf planet Ceres.
The spacecraft is powered by an ion thruster – an engine that accelerates ion molecules to create forward momentum. This enduring propulsion system makes efficient use of fuel and electricity, and will allow Dawn to become the first spacecraft to orbit two deep space destinations.
To date, Dawn has traveled around 1.7 billion miles, using the gas giant Jupiter to give the robotic explorer a gravity assist as it made its way towards its first target, Vesta, gaining orbit in July 2011. During its year-long stay around the giant asteroid, Dawn took in excess of 30,000 images of Vesta, gaining many valuable insights in the process. Finally, on Sept. 7, 2012, the robotic pioneer set sail for her final destination, Ceres – a rocky minor planet that is believed to contain large amounts of ice, and possibly even a hidden ocean under its enigmatic outer shell.
Processed image of Ceres as captured from the Dawn spacecraft (Image: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
However, mission controllers have not had things all their own way. Over the course of its epic voyage through deep space, Dawn suffered a number of malfunctions, the most recent of which, caused by a collision with a high-energy radiation particle, forced the probe to enter a safe mode, shutting down the spacecraft's active ion thruster in the process. NASA personnel swiftly implemented a recovery protocol, switching to another ion engine as they implemented a work-around, allowing Dawn to quickly resume her burn towards Ceres with little to no detriment to the mission.
The most detailed images of the dwarf planet are currently provided by NASA's Hubble Space Telescope, and whilst Dawn's images cannot yet match the resolution of the legendary telescope (currently snapping images at around 80 percent the quality of NASA's flagship platform), she is getting closer. The spacecraft has already returned some stunning images, the most recent of which captured Ceres at a resolution of 27 pixels across, roughly three times better than her previous attempts. Before long, Dawn will be close enough to its quarry to outstrip the ability of humanity's most famous telescope, as she races towards orbit capture, an event expected to take place March 6.
"The team is very excited to examine the surface of Ceres in never-before-seen detail," says principal investigator for Dawn, Chris Russel. "We look forward to the surprises this mysterious world may bring."